1. Field of the Invention
The present invention relates to the recording of copy protected broadcast, more particularly, the present invention relates to the implementation of copied-once protection of broadcast.
2. Art Background
Today there is a number of different broadcast media in which users can view a variety of types of programming. Certain types of programming such as "Pay Per View" are typically a surcharge over what a user pays to receive a particular broadcast. An example of this is found in cable television as well as in satellite transmission broadcast (STB). To protect from unauthorized copying of certain programming, different techniques have been developed that encode information into the broadcast signal that enables a user to view the broadcast, but when an attempt is made to record the broadcast, the data is obscured.
FIG. 1 is a simplified block diagram of a conventional setup of a home system. The system includes a broadcast receiver, such as a television or satellite broadcast receiver shown. The receiver 10 typically includes circuitry 15 to perform some initial signal processing, such as a Domodulation, Error Correction, a decoder 20 to decode the transport layer of the broadcast data packet, circuitry 25 to decompress the video and a controller 30 to control the receiver. In addition, the receiver may include copy protect circuitry 35 that encodes a signal into the received broadcast such that the broadcast can be displayed by the display device 40 but not recorded. If the broadcast is recorded, the copy protect signal encoded into the broadcast causes the recorded broadcast signal to be corrupted. One example of a copy protect process is described in Ryan, U.S. Pat. No. 5,130,810.
A recording device, such as a video cassette recorder 45, is typically connected to the output of the receiver 10. As is well known in the art, the signal input to the recording device 45 is typically conditioned prior to recording on the recording medium. An automatic gain control process is performed by circuit 50 to place the video signal within acceptable signal ranges for recording. A circuit 52 is used to separate out the sync signals used to broadcast. Subsequently the luminance and chrominance are separated, circuit 55, for processing, circuits 60, 65, and recombined, circuit 70, for output to the recording medium 75.
It would be advantageous to provide the user the opportunity to select a one-time recording capability for a certain broadcast ("Pay-Per-Record"). This is envisioned to eliminate the need to travel to a store to purchase a video. Therefore, it is desirable to provide a one-time copy capability such that after the one copy is made, subsequent copies are prohibited.